The invention relates to an axially adjustable steering column for vehicles with telescoping jacket parts.
German Patent Document DE-PS 26 10 139 discloses an axially adjustable steering column for vehicles in which the steering column jacket components which can be adjusted in a telescopic fashion with respect to one another can be attached to one another by means of a clamp connection. The clamp connection has a threaded pin which can be moved radially with respect to the longitudinal axis of the steering column jacket components, is mounted on the outer steering column jacket component in a threaded section and can be attached in a non-positively engaging manner to the internal steering column jacket component by means of its rotation. The rotation of the threaded pin occurs by means of a manual wheel mounted on it.
When the threaded pin is actuated manually, a person adjusting the axial position of the steering column by turning the threaded pin is not given any information as to how far he has to turn the manual wheel until the threaded pin is loosened far enough or tightened tightly enough. Therefore after the displaceable steering column jacket component is locked there remains the unpleasant sensation of not knowing whether the locking will perhaps soon be released again automatically for example due to vibrations. This is possible in particular if the threaded pin is not impeded from coming loose, by the effect of a further force, in its screwed-in position which applies a pressure force.
German Patent Document DOS 34 09 988 shows an axially adjustable steering column with two tubes whose movement relative to one another can be prevented by means of a manually actuable lock. On unlocking, a manual lever acts here by means of a control cable on a wedge body which thus moves a locking tooth out of its corresponding toothing. A spring pulls the wedge body automatically back into its locking position, which body otherwise is not supported in its locking position which acts counter to its displacement into the unlocked position.
An object of the invention is to provide an arrangement accommodating simple releasing and securing of a clamp connection for the telescoping jacket parts of an axially adjustable steering column.
This object is achieved in preferred embodiments of the invention by providing an axially adjustable steering column system for vehicles comprising:
an axially displaceable steering shaft,
an outer and an inner steering column jacket part surrounding the steering shaft, said steering column jacket parts being configured to be pushed together in a telescopic fashion with axial movement with respect to one another, and
a clamp connection for selectively clampingly attaching the two steering column jacket parts to one another to hold them in their adjusted axial position,
wherein the clamp connection includes at least one threaded pin which is radially movable with respect to a longitudinal axis of the steering column and is received on the outer steering column jacket part in a threaded section and after its screwing-in movement presses against the inner steering column jacket part, wherein a spring-loaded control cable is provided which acts in a rotating fashion on the threaded pin, and wherein the control cable surrounds a pin connecting part on the threaded pin resting against a circular cross-section at least over a distance of one arcuate section of the threaded pin.
With a control cable which acts in a turning fashion on a threaded pin which thus attaches two steering column jacket components to one another in a non-positively engaging manner, it is possible to continue to act in a fixing manner on the threaded pin in its release position and in its locking position. The actuation of the threaded pin can then be performed from a site which is remote from the clamping device.
So that a pin connecting component can be correctly positioned on the threaded pin, which pin connecting component connects the control cable to the threaded pin is tensioned rapidly in its correct position in which the control cable is at least partially wound around the pin connecting component and the control cable is tensioned, the pin connecting component is constructed as a mountable cap which can be placed by means of an internal toothing in a positively engaging manner in a plurality of positions on the threaded pin provided with a matching toothing.
The threaded pin acts in its locking position with a relatively high degree of force on the internal steering column jacket component. Therefore, when it is loosened the required turning moment is high for which reason high actuating forces are also necessary in the event of a mechanical actuation of the control cable. For this reason, the threaded pin is divided up radially into two sections between which a roller bearing which permits a rotation of the sections with respect to one another is located in the axial direction, and thus firstly the section operatively connected to the control cable in the roller bearing is loosened and the section resting against the internal steering column component can be raised by the loosened section in the axial direction.
An actuation switch acting as a pull actuation which has two fixed positions prevents an operator from unintentionally using the clamping device since the released and the locking position of the threaded pin can be predetermined by these fixed positions.
In the clamping device, a plurality of threaded pins can be provided in order, for example, to increase the clamping force. Here, the control cable can run in succession under tension to the threaded pins and be connected in each case to the latter in a tensile fashion, as a result of which the threaded pins can be rotated at the same time and to the same degree.
In order to retain the threaded pin securely in its locking position, it is advantageous to load it continuously by a moment in the locking direction, which can be realized by means of a tension spring which is connected to the threaded pin by means of a control cable. The control cable is at least partially wrapped around the pin connecting component and the tension and spring is mounted on the outer steering column jacket component. When there is a single threaded pin, the tension spring can be directly attached to the end of the control cable opposite a pull actuation. If the clamping device should have a plurality of threaded pins, it is better to provide a pulling cable for the common loosening of the threaded pins and to connect in each case a separate pulling cable with an extra tension spring for their subjection to locking forces, which springs can apply approximately the same locking force on each threaded pin.
This clamping device can equally serve to eliminate the play of two steering column jacket components which require a certain play between the steering column jacket walls for their displacement and have a different locking device constructed in any desired way for fixing them. Here, the control cable which acts on the threaded pins can simultaneously also act on an actuation component of the locking device, as a result of which the locking and the elimination of the play of the steering column jacket components can be performed synchronously.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.